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Accueil du site → Doctorat → Allemagne → Amphibian communities of the dry forest of Western Madagascar : taxonomy, ecology and conservation

Bayerischen Julius-Mawimilians-Universität Würzburg (2006)

Amphibian communities of the dry forest of Western Madagascar : taxonomy, ecology and conservation

Glos, Julian

Titre : Amphibian communities of the dry forest of Western Madagascar : taxonomy, ecology and conservation

Amphibiengemeinschaften im westmadagassischen Trockenwald : Taxonomie, Ökologie und Naturschutz

Auteur : Glos, Julian

Université de soutenance : Bayerischen Julius-Mawimilians-Universität Würzburg

Grade : Doktor der Naturwissenschaftlichen 2006

The amphibian fauna of the Kirindy dry forest in western Madagascar Abstracts of chapter 5 and 6 Living apart together – patterns of tadpole communities in a western Madagascan dry forest Whether communities are established in a deterministic or in a stochastic manner depends to a large degree on the spatial scale considered. In this study we use a tadpole community in the dry forest of western Madagascar to show that when within-site habitat diversity is considered, communities may also differ in two community parameters (species composition and species richness) within one geographic scale. Forest ponds and riverbed ponds are two types of breeding habitat that are both used by anurans but that differ generally in their temporal availability, predation pressure, and environmental characteristics. In forest ponds, tadpole communities were very predictable by the physical properties of the ponds and by their vegetation characteristics. In contrast, the riverbed communities were not predictable. We offer two hypotheses to explain this phenomenon. This study clearly demonstrates differing patterns in community organization in two natural habitats within one site, and therefore, highlights the importance of considering local conditions and within-site habitat diversity in community studies. Modeling the habitat use of an endangered dry-forest frog from Western Madagascar A crucial factor for the successful reproduction and thus conservation of an amphibian species is the availability of suitable waters as breeding sites. In this chapter, we examine the use of breeding sites of an endangered, local endemic frog of Western Madagascar, Aglyptodactylus laticeps, over a three year period. Logistic regression was used to model the relationship between the species’ breeding habitat use and environmental variables. This model was aimed to be predictive, rather than explanatory, and only environmental variables were included that are assessable in a time and cost effective manner, and that can therefore be used as an easy-to-use management tool in applied conservation. On the local scale of the Kirindy concession, A. laticeps is restricted to forest with a relatively low degree of disturbance and closed canopy cover. The model identified three environmental variables that suffice to satisfactorily predict the use of respective breeding sites, namely leaf litter, vegetation coverage and surface water plants. Based on these results, we present recommendations for the conservation management of this frog. Furthermore, the presence or absence of this species within its natural range indicates the relative degree of environmental integrity of its habitat, and we therefore consider this species as a suitable indicator species of temporary aquatic habitats within the dry forest that are characterized by a low water permanency and high leaf litter coverage. This study demonstrates that models constructed from basic ecological knowledge of relevant species may serve as valuable management tools in applied more

Mots clés : Gemeinschaftsökologie ; Habitatmodel ; Kaulquappen ; Räuber-Beute Interaktionen community ecology ; habitat model ; predator-prey interactions ; tadpoles


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